diff --git a/CHANGELOG.md b/CHANGELOG.md
index e5bbef9..f7e2d2c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
 ### Added
+- A toggle button for copying non-unique patterns before editing. When enabled
+  and if the pattern is used in multiple places, the pattern is copied first.
+  ([#77][i77])
 - User can define own keybindings in
   `os.UserConfigDir()/sointu/keybindings.yaml` ([#94][i94], [#151][i151])
 - A small number above the instrument name identifies the MIDI channel /
@@ -226,6 +229,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 [0.1.0]: https://github.com/vsariola/sointu/compare/4klang-3.11...v0.1.0
 [i65]: https://github.com/vsariola/sointu/issues/65
 [i68]: https://github.com/vsariola/sointu/issues/68
+[i77]: https://github.com/vsariola/sointu/issues/77
 [i94]: https://github.com/vsariola/sointu/issues/94
 [i112]: https://github.com/vsariola/sointu/issues/112
 [i116]: https://github.com/vsariola/sointu/issues/116
diff --git a/song.go b/song.go
index 698275e..fbe2ad0 100644
--- a/song.go
+++ b/song.go
@@ -137,7 +137,10 @@ func (s Track) Note(pos SongPos) byte {
 	return s.Patterns[pat][pos.PatternRow]
 }
 
-func (s *Track) SetNote(pos SongPos, note byte) {
+// SetNote sets the note at the given position. If uniquePatterns is true, the
+// pattern is copied to a new pattern if the pattern is used by more than one
+// order row.
+func (s *Track) SetNote(pos SongPos, note byte, uniquePatterns bool) {
 	if pos.OrderRow < 0 || pos.PatternRow < 0 {
 		return
 	}
@@ -163,13 +166,31 @@ func (s *Track) SetNote(pos SongPos, note byte) {
 	for pat >= len(s.Patterns) {
 		s.Patterns = append(s.Patterns, Pattern{})
 	}
-	if pos.PatternRow >= len(s.Patterns[pat]) && note == 1 {
-		return
+	if uniquePatterns {
+		uses := 0
+		maxPat := 0
+		for _, p := range s.Order {
+			if p == pat {
+				uses++
+			}
+			if p > maxPat {
+				maxPat = p
+			}
+		}
+		if uses > 1 {
+			newPattern := append(Pattern{}, s.Patterns[pat]...)
+			pat = maxPat + 1
+			if pat >= 36 {
+				return
+			}
+			for pat >= len(s.Patterns) {
+				s.Patterns = append(s.Patterns, Pattern{})
+			}
+			s.Patterns[pat] = newPattern
+			s.Order.Set(pos.OrderRow, pat)
+		}
 	}
-	for pos.PatternRow >= len(s.Patterns[pat]) {
-		s.Patterns[pat] = append(s.Patterns[pat], 1)
-	}
-	s.Patterns[pat][pos.PatternRow] = note
+	s.Patterns[pat].Set(pos.PatternRow, note)
 }
 
 // Get returns the value at index; or 1 is the index is out of range
@@ -182,6 +203,9 @@ func (s Pattern) Get(index int) byte {
 
 // Set sets the value at index; appending 1s until the slice is long enough.
 func (s *Pattern) Set(index int, value byte) {
+	if value == 1 && index >= len(*s) {
+		return
+	}
 	for len(*s) <= index {
 		*s = append(*s, 1)
 	}
diff --git a/tracker/bool.go b/tracker/bool.go
index 9093d0d..f050e20 100644
--- a/tracker/bool.go
+++ b/tracker/bool.go
@@ -21,6 +21,7 @@ type (
 	UnitSearching   Model
 	UnitDisabled    Model
 	LoopToggle      Model
+	UniquePatterns  Model
 )
 
 func (v Bool) Toggle() {
@@ -45,6 +46,7 @@ func (m *Model) Follow() *Follow                   { return (*Follow)(m) }
 func (m *Model) UnitSearching() *UnitSearching     { return (*UnitSearching)(m) }
 func (m *Model) UnitDisabled() *UnitDisabled       { return (*UnitDisabled)(m) }
 func (m *Model) LoopToggle() *LoopToggle           { return (*LoopToggle)(m) }
+func (m *Model) UniquePatterns() *UniquePatterns   { return (*UniquePatterns)(m) }
 
 // Panic methods
 
@@ -185,3 +187,10 @@ func (t *LoopToggle) setValue(val bool) {
 	m.setLoop(newLoop)
 }
 func (m *LoopToggle) Enabled() bool { return true }
+
+// UniquePatterns methods
+
+func (m *UniquePatterns) Bool() Bool        { return Bool{m} }
+func (m *UniquePatterns) Value() bool       { return m.uniquePatterns }
+func (m *UniquePatterns) setValue(val bool) { m.uniquePatterns = val }
+func (m *UniquePatterns) Enabled() bool     { return true }
diff --git a/tracker/gioui/keyevent.go b/tracker/gioui/keyevent.go
index 86d3bef..d315173 100644
--- a/tracker/gioui/keyevent.go
+++ b/tracker/gioui/keyevent.go
@@ -220,6 +220,8 @@ func (t *Tracker) KeyEvent(e key.Event, gtx C) {
 		t.UnitDisabled().Bool().Toggle()
 	case "LoopToggle":
 		t.LoopToggle().Bool().Toggle()
+	case "UniquePatternsToggle":
+		t.UniquePatterns().Bool().Toggle()
 	// Integers
 	case "InstrumentVoicesAdd":
 		t.Model.InstrumentVoices().Int().Add(1)
diff --git a/tracker/gioui/note_editor.go b/tracker/gioui/note_editor.go
index 48d982d..59de3d6 100644
--- a/tracker/gioui/note_editor.go
+++ b/tracker/gioui/note_editor.go
@@ -59,13 +59,15 @@ type NoteEditor struct {
 	SubtractOctaveBtn   *ActionClickable
 	NoteOffBtn          *ActionClickable
 	EffectBtn           *BoolClickable
+	UniqueBtn           *BoolClickable
 
 	scrollTable  *ScrollTable
 	tag          struct{}
 	eventFilters []event.Filter
 
-	deleteTrackHint string
-	addTrackHint    string
+	deleteTrackHint           string
+	addTrackHint              string
+	uniqueOffTip, uniqueOnTip string
 }
 
 func NewNoteEditor(model *tracker.Model) *NoteEditor {
@@ -79,6 +81,7 @@ func NewNoteEditor(model *tracker.Model) *NoteEditor {
 		SubtractOctaveBtn:   NewActionClickable(model.SubtractOctave()),
 		NoteOffBtn:          NewActionClickable(model.EditNoteOff()),
 		EffectBtn:           NewBoolClickable(model.Effect().Bool()),
+		UniqueBtn:           NewBoolClickable(model.UniquePatterns().Bool()),
 		scrollTable: NewScrollTable(
 			model.Notes().Table(),
 			model.Tracks().List(),
@@ -93,6 +96,8 @@ func NewNoteEditor(model *tracker.Model) *NoteEditor {
 	}
 	ret.deleteTrackHint = makeHint("Delete\ntrack", "\n(%s)", "DeleteTrack")
 	ret.addTrackHint = makeHint("Add\ntrack", "\n(%s)", "AddTrack")
+	ret.uniqueOnTip = makeHint("Duplicate non-unique patterns", " (%s)", "UniquePatternsToggle")
+	ret.uniqueOffTip = makeHint("Allow editing non-unique patterns", " (%s)", "UniquePatternsToggle")
 	return ret
 }
 
@@ -145,6 +150,7 @@ func (te *NoteEditor) layoutButtons(gtx C, t *Tracker) D {
 			return in.Layout(gtx, numStyle.Layout)
 		}
 		effectBtnStyle := ToggleButton(gtx, t.Theme, te.EffectBtn, "Hex")
+		uniqueBtnStyle := ToggleIcon(gtx, t.Theme, te.UniqueBtn, icons.ToggleStarBorder, icons.ToggleStar, te.uniqueOffTip, te.uniqueOnTip)
 		return layout.Flex{Axis: layout.Horizontal, Alignment: layout.Middle}.Layout(gtx,
 			layout.Rigid(func(gtx C) D { return layout.Dimensions{Size: image.Pt(gtx.Dp(unit.Dp(12)), 0)} }),
 			layout.Rigid(addSemitoneBtnStyle.Layout),
@@ -153,6 +159,7 @@ func (te *NoteEditor) layoutButtons(gtx C, t *Tracker) D {
 			layout.Rigid(subtractOctaveBtnStyle.Layout),
 			layout.Rigid(noteOffBtnStyle.Layout),
 			layout.Rigid(effectBtnStyle.Layout),
+			layout.Rigid(uniqueBtnStyle.Layout),
 			layout.Rigid(Label("  Voices:", white, t.Theme.Shaper)),
 			layout.Rigid(voiceUpDown),
 			layout.Flexed(1, func(gtx C) D { return layout.Dimensions{Size: gtx.Constraints.Min} }),
diff --git a/tracker/list.go b/tracker/list.go
index 7548be5..2a7db6d 100644
--- a/tracker/list.go
+++ b/tracker/list.go
@@ -667,8 +667,8 @@ func (v *NoteRows) swap(i, j int) (ok bool) {
 	for _, track := range v.d.Song.Score.Tracks {
 		n1 := track.Note(ipos)
 		n2 := track.Note(jpos)
-		track.SetNote(ipos, n2)
-		track.SetNote(jpos, n1)
+		track.SetNote(ipos, n2, v.uniquePatterns)
+		track.SetNote(jpos, n1, v.uniquePatterns)
 	}
 	return true
 }
@@ -679,7 +679,7 @@ func (v *NoteRows) delete(i int) (ok bool) {
 	}
 	pos := v.d.Song.Score.SongPos(i)
 	for _, track := range v.d.Song.Score.Tracks {
-		track.SetNote(pos, 1)
+		track.SetNote(pos, 1, v.uniquePatterns)
 	}
 	return true
 }
@@ -730,7 +730,7 @@ func (v *NoteRows) unmarshal(data []byte) (from, to int, err error) {
 		for j, note := range arr {
 			y := j + from
 			pos := v.d.Song.Score.SongPos(y)
-			v.d.Song.Score.Tracks[i].SetNote(pos, note)
+			v.d.Song.Score.Tracks[i].SetNote(pos, note, v.uniquePatterns)
 		}
 	}
 	return
diff --git a/tracker/model.go b/tracker/model.go
index 6cca46a..625f95d 100644
--- a/tracker/model.go
+++ b/tracker/model.go
@@ -54,13 +54,14 @@ type (
 		changeSeverity ChangeSeverity
 		changeType     ChangeType
 
-		panic        bool
-		recording    bool
-		playing      bool
-		playPosition sointu.SongPos
-		loop         Loop
-		follow       bool
-		quitted      bool
+		panic          bool
+		recording      bool
+		playing        bool
+		playPosition   sointu.SongPos
+		loop           Loop
+		follow         bool
+		quitted        bool
+		uniquePatterns bool
 
 		cachePatternUseCount [][]int
 
diff --git a/tracker/model_test.go b/tracker/model_test.go
index 32ff896..8158372 100644
--- a/tracker/model_test.go
+++ b/tracker/model_test.go
@@ -60,6 +60,7 @@ func (s *modelFuzzState) Iterate(yield func(string, func(p string, t *testing.T)
 	s.IterateBool("Effect", s.model.Effect().Bool(), yield, seed)
 	s.IterateBool("CommentExpanded", s.model.CommentExpanded().Bool(), yield, seed)
 	s.IterateBool("Follow", s.model.Follow().Bool(), yield, seed)
+	s.IterateBool("UniquePatterns", s.model.UniquePatterns().Bool(), yield, seed)
 	// Strings
 	s.IterateString("FilePath", s.model.FilePath().String(), yield, seed)
 	s.IterateString("InstrumentName", s.model.InstrumentName().String(), yield, seed)
diff --git a/tracker/table.go b/tracker/table.go
index 0d1182d..e8a38eb 100644
--- a/tracker/table.go
+++ b/tracker/table.go
@@ -481,7 +481,7 @@ func (v *Notes) add(rect Rect, delta int) (ok bool) {
 				newVal = 255
 			}
 			// only do all sets after all gets, so we don't accidentally adjust single note multiple times
-			defer v.d.Song.Score.Tracks[x].SetNote(pos, byte(newVal))
+			defer v.d.Song.Score.Tracks[x].SetNote(pos, byte(newVal), v.uniquePatterns)
 		}
 	}
 	return true
@@ -540,7 +540,7 @@ func (v *Notes) unmarshalAtCursor(data []byte) bool {
 				continue
 			}
 			pos := v.d.Song.Score.SongPos(y)
-			v.d.Song.Score.Tracks[x].SetNote(pos, q)
+			v.d.Song.Score.Tracks[x].SetNote(pos, q, v.uniquePatterns)
 		}
 	}
 	return true
@@ -562,7 +562,7 @@ func (v *Notes) unmarshalRange(rect Rect, data []byte) bool {
 				continue
 			}
 			pos := v.d.Song.Score.SongPos(y)
-			v.d.Song.Score.Tracks[x].SetNote(pos, a)
+			v.d.Song.Score.Tracks[x].SetNote(pos, a, v.uniquePatterns)
 		}
 	}
 	return true
@@ -609,7 +609,7 @@ func (m *Notes) SetValue(p Point, val byte) {
 	}
 	track := &(m.d.Song.Score.Tracks[p.X])
 	pos := m.d.Song.Score.SongPos(p.Y)
-	(*track).SetNote(pos, val)
+	(*track).SetNote(pos, val, m.uniquePatterns)
 }
 
 func (v *Notes) FillNibble(value byte, lowNibble bool) {